Business Segments (Statements of Operations) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Segment Reporting Information [Line Items]
Revenues	$ 318.2	$ 210.1	$ 171.4	$ 173.7	$ 273.9	$ 194.6	$ 163.0	$ 158.9	$ 873.4	$ 790.4	$ 885.6
Gross profit									225.9	209.6	246.4
Selling, general and administrative expenses									210.4	192.0	195.8
Operating profit (loss)	37.0	14.8	7.7	8.0	42.3	13.3	3.6	4.9	67.5	64.1	94.2
Interest expense									6.1	8.7	10.8
Interest income									(0.2)	(0.3)	(0.3)
Other (income) expense									3.6	(56.6)	21.0
Income tax provision									15.8	32.8	15.6
Income from continuing operations	23.7	10.2	3.5	4.8	29.9	8.2	1.4	40.0	42.2	79.5	47.1
NACoal
Segment Reporting Information [Line Items]
Revenues	50.9	38.0	19.2	24.3	23.5	21.0	19.4	17.9	132.4	81.8	156.8
Gross profit									28.0	15.3	37.9
Selling, general and administrative expenses									36.8	26.6	28.2
Operating profit (loss)	13.5	8.6	9.2	11.9	13.4	7.0	5.3	9.5	43.2	35.2	53.3
Interest expense									2.9	3.0	3.3
Interest income									(0.2)	(0.3)	(0.3)
Other (income) expense									(1.3)	(1.4)	(0.1)
Income tax provision									9.0	4.5	10.8
Income from continuing operations	8.3	8.2	7.1	9.2					32.8	29.4	39.6
HBB
Segment Reporting Information [Line Items]
Revenues	181.2	124.8	110.7	104.9	161.4	126.7	104.3	100.6	521.6	493.0	515.7
Gross profit									102.3	97.2	111.1
Selling, general and administrative expenses									66.5	63.4	65.2
Operating profit (loss)	19.9	8.7	5.1	2.1	19.0	7.9	3.6	3.3	35.8	33.8	45.9
Interest expense									2.7	5.2	7.2
Other (income) expense									0.3	0.8	0.3
Income tax provision									11.6	9.4	14.0
Income from continuing operations	12.7	5.3	2.2	1.0					21.2	18.4	24.4
KC
Segment Reporting Information [Line Items]
Revenues	88.9	48.2	42.3	45.3	91.4	48.9	40.0	40.9	224.7	221.2	219.6
Gross profit									95.8	97.4	97.7
Selling, general and administrative expenses									100.4	94.9	91.8
Operating profit (loss)	7.0	(1.9)	(5.1)	(4.6)	12.8	(0.6)	(4.3)	(5.4)	(4.6)	2.5	5.9
Interest expense									0.5	0.5	0.3
Other (income) expense									0	0.1	0.1
Income tax provision									(2.0)	0.8	2.0
Income from continuing operations	4.1	(1.2)	(3.2)	(2.8)					(3.1)	1.1	3.5
NACCO and Other
Segment Reporting Information [Line Items]
Gross profit									(0.3)	(0.2)	(0.2)
Selling, general and administrative expenses									6.7	7.1	10.6
Operating profit (loss)	(3.4)	(0.6)	(1.5)	(1.5)	(2.8)	(0.9)	(1.1)	(2.5)	(7.0)	(7.3)	(10.8)
Other (income) expense									4.6	(56.1)	20.7
Income tax provision									(3.0)	18.1	(11.1)
Income from continuing operations	(4.4)	(1.1)	(1.7)	(1.4)					(8.6)	30.7	(20.4)
Eliminations
Segment Reporting Information [Line Items]
Revenues	(2.8)	(0.9)	(0.8)	(0.8)	(2.4)	(2.0)	(0.7)	(0.5)	(5.3)	(5.6)	(6.5)
Gross profit									0.1	(0.1)	(0.1)
Operating profit (loss)	0	0	0	0.1	(0.1)	(0.1)	0.1	0	0.1	(0.1)	(0.1)
Income tax provision									0.2	0	(0.1)
Income from continuing operations	$ 3.0	$ (1.0)	$ (0.9)	$ (1.2)					$ (0.1)	$ (0.1)	$ 0